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Tribometers and Surfaces - ASTM F2508 and ANSI B101.3

Updated: Oct 17, 2018

ASTM's recently published comparison between ASTM F2508-16 (F2508) and ANSI/NFSI B101.3-12 (B101.3) by Bevill and Baker provides a bit of insight into the often confusing world of slip resistance testing. The intent of the two standards are quite different in that B101.3 establishes the guideline for acceptable levels of slip resistance based upon the wet dynamic coefficient of friction, while F2508 provide a methodology for validating tribometers against a standard reference system.

At the time of publication, B101.3 required that the tribometer being used for testing have a digital readout, which effectively eliminated the use of the English XL or MK IIIB in favor of the BOT 3000 since the English XL and MK IIIB provided measurements using analog scales. In fact, ANSI A326.3-17 American National Standard Test Method for Measuring Dynamic Coefficient of Friction of Hard Surface Flooring Materials (A326.3) specifically names the BOT3000e. This was published in spite of the fact that both the English XL and the MK IIIB both passed the independent validation procedures of F2508.

The B101.3 standard establishes numeric threshold for slip resistance, 0.30 to 0.42 is considered "acceptable" slip resistance, and greater than 0.42 is considered "highly slip resistant." The extensive testing performed by Bevill and Baker found that there was a high correlation between the testing results from the BOT and the English XL. As expected, the actual numeric results differed, as the two instruments have differing scales (i.e., a 0.30 measurement on an English XL would be considered slippery, but is considered acceptable by the BOT 3000e). Both instruments indicated that the wet ASTM reference ceramic tile specimen were slip resistant (0.65 for English XL and 0.94 for BOT 3000e); and that granite and porcelain tiles were not acceptable. The ASTM reference vinyl tile was measured to be unacceptable by the English XL (0.26). This same tile was measured in the range of acceptable, but increased probability of slipping by the BOT 3000e (0.37).

As concluded in the Bevill and Baker research, the testing of these instruments against the ASTM reference tiles revealed a linear correlation. This support the conclusion that both machines are an acceptable methodology of testing for slip resistance when used in accordance with the manufacturer's guidelines. Furthermore, the data indicates that the linear relationship would allow for a correlation between the "acceptable" range on the BOT 3000 to the slip resistance measurements from the English XL.


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